NO\ EMBER, 1936
INDUSTRIAL AND EKGINEERING CHEMISTRY
In using the compositions described above for lacquer purposes, incorporation of a certain amount of plasticizer is usually desirable, Although no extensive study of plasticizers was made in this investigation, it was found that some plasticizers tend t o decrease the compatibility of resins with the cellulose mixed esters, while others increase or have little effect on the maximum amounts which may be used. Below are described lacquer compositions which have been found satisfactory in experimental work from the standpoints of compatibility, adhesion, surface hardness, and uniformity in spraying (in weight per cent) :
Cellulose ester Resin Plasticizer Solvent
Cellulose Acetate Propionate (Acetyl 12.5%, Propionyl 32.5%) 100 25 50 1000
Cellulose Acetate Butyrate (Acetyl lo%, Butyryl 38%) 100 75 50 1000
The solvent used was composed of 10 per cent ethyl acetate, 20 butyl acetate, 20 ethyl alcohol, 10 butyl alcohol, and 40 toluene. Compositions containing esters, gum, elemi, dammar, and rosin were each employed with the following plasticizers: methyl phthalate, butyl phthalate] tricresyl phosphate] and butyl tartrate.
1313
Absorption of Carbon Dioxide by Amines Di- and Triethanolamine and Tetramine L. L. HIRST AND I. I. PINKEL U. S. Bureau of Mines, Experiment Station, Pittsburgh,Pa.
Literature Cited British Celanese, British Patent 298,608 (1930). I b i d . , 307,292 (1929). DeStubner, I b i d . , 297,679 (1930). Dreyfus, Ihid., 222,168 (1934); 345,531 (1930). Eastman Kodak Co., U. S. Patents 1,958,707, 1,958,714, 1,958,715, 1,969,473, 1,973,488, 1,976,359 (1934).
Eberlin and Blanchard, I b i d . , 1,899,186 (1933). Gardner, Natl. Paint Varnish Lacquer Assoc., Circ 338, 657 (1928).
Hagedorn and Moeller, Cellulosechem., 12, 29 (1931) I. G. Farbenindustrie, British Patent 367,932 (1930) ; French Patent 716,397 (1931) ; German Patent 564,771 (1932). Kocher, U. S. Patent 1,973,489 (1934). Kodak Path& French Patent 736,211 (1931). Schnuerle, German Patent 399,911 (1922). Sheppard and Newsome, J. Phz/s. Chem., 39, 143 (1935). U. S. Patents 1,185,514; 1,558,442; 1,812,335; 1,828,449; 1,849,108; 1,881,219; 1,897,015; 1,902,255; 1,902,256; 1,902,257; 1,902,337; 1,907,554; 1,909,195; 1,940,727; 1,941,262; 1,941,708; British Patents 285,049: 296,675; 298,616; 299,066; 299,067; 307,289; 311,657; 315,807; 315,808; 316,322; 317,454; 322,540; 322,541; 322,543; 335,582; 338,002; 338,024; 340,102; 340,104; 341,413; French Patents 669,278; 344,626; 366,586; 367,759; 453,395; 47,104; German Patents 404,024; Canadian 293,641; 295,242; 297,081 ; 297,082; 297,083; 297,084; 317,117; 319,150; 319,151; 319,152; 319,729; 319,730; 319,731; 324,633; 325,615; 329,371; 329,708; 329,709; 329,710. U. S. Patents 1,896,581; 1,896,915; 1,917,407; 1,983,006; British Patents 367.817: 399.191: 402.733: French Patents 517,451; 527.706; 679,607; 704,862;' 732,663; Canadian Patents 293,807; 345.673. Van Heuckeroth, Natl. Paint Varnish Lacquer Assoc., C ~ T C 458 . 97-100 (1934). Wiggam and Gloor, IKD. ENQ.CHEM.,26, 551 (1934). Worden, "Technology of Cellulose Esters," Vol. VIII, p, 2639, New York, D. Van Nostrand Co., 1921.
RECEIVED September 12, 1936. Presented before the Division of Paint a n d Varnish Chemistry a t t h e 92nd Meeting of t h e American Chemical Society, Pittsburgh, Pa., September 7 t o 11. 1936.
To select a solution for scrubbing carbon dioxide from hydrogen-carbon dioxide mixtures, laboratory experiments were made using a glass column packed with glass rings. Fifty per cent solutions of di- and triethanolamine and 5, 10, and 25 per cent solutions of Tetramine were used to reduce the carbon dioxide content of the scrubbed gas to less than 0.1 per cent. Fifty per cent triethanolamine solution is much less efficient than either 50 per cent diethanolamine or 5 per cent Tetramine solutions. Equal volumes of 50 per cent diethanolamine or 10 per cent Tetramine solutions are necessary to reduce the carbon dioxide content of the scrubbed gas to 0.1 per cent or less.
QH
YDROGEN for use in the Bureau of
Mines coal hydrogenation program will be produced in a three-step process. Water gas will be generated b y the reaction between steam and natural gas, most of the carbon monoxide will be oxidized by additional steam a t a lower temperature, and carbon dioxide will be removed from the resulting gas by scrubbing. T h e gas to be scrubbed will consist of approximately 80 per cent hydrogen and 20 per cent carbon dioxide, along with small percentages of nitrogen, carbon monoxide, and methane; it is desired to reduce t h e carbon dioxide content to 0.1 per cent or less. The laboratory experiments reported in this paper were intended to select the most suitable scrubbing solution and to furnish data needed for t h e design of t h e larger equipment. The apparatus is shown diagrammatically in Figure 1: The column, g, is 3.6 em. in diameter andispackedfor alength of 150 cm. with glass rings 0.87 cm. in diameter and 1 cm. long. Scrubbing solution from the 8-liter reservoir, a,flows through the 0.5-liter preheater, 6 , the constant-head vessel, c, the flowmeter,
INDUSTRIAL AXD ENGINEERING CHEMISTRY
1314
VOL. 28, KO. 11
these experiments had been previously used and then regenerated by boiling. T h e equilibrium absorption is greater a t lower temperatures, but t h e rate of absorption is probably lower. It was found in preliminary experiments that t h e best results were obtained a t inlet amine temperatures of 38" to 40" C., and most of the runs reported were made a t that temperature. TABLE11. ABSORPTIONOF CARBON DIOXIDEFROM HYDROGEN-CARBON DIOXIDEhfIXTURES B Y TETR.4MINE SOLCTIOXP Scrubbing Soln. Liters Per cent per hr. tetramine
FIGURE 1. GLASS TOWERUSED IN SCRUBHYDROGEN-CARBON DIOXIDEMIXTURES WITH AMINE SOLUTIONS
BING
d, the drip head, h, the column packing, j , and finally leaves the apparatus at the stopcock, k , which is set so as to maintain a liquid seal. Hydrogen and carbon dioxide from steel storage cylinders pass through flowmeters m and 1, respectively, enter the base of the column at n, rise countercurrent to the scrubbing liquid, and pass out at p . In the experiments with di- and triethanolamine solutions, the column is heated electrically throughout its length, resulting in temperature gradients of between 5' and 10' C. from top to bottom. In the experiments with Tetramine solutions three electrically heated water jackets cover the lower three-fourths of the column and the upper fourth is electrically heated as before. By suitable addition of cold water to the water jackets, it is possible to maintain nearly isothermal conditions throughout the column, as shown by thermometers 3, 4, 5 , 6, and 7. A window is provided in the upper section of the column in order to observe the distribut'ion of the scrubbing solution over the packing. To avoid delay in wetting the packing, it is necessary to fill the ent'ire column with the scrubbing solution and then drain to the operating level before starting the gas flow. Even with this precaution satisfactory wetting cannot be obtained at liquid flows of less than 2.4 liters per hour.
a
b
2 7
10 10 10 10
3 6
R u n No.
Liters Soln. per Hr.
-Temp. of Soln., C . 7 Entering Leaving column column Diethanolamine
Liters Gas per Hr. a t 20' C . , 750 Mm.
Per Cent CO, in Scrubbed Gas
---Inlet
GasMax. liters/hr. scrubbed t o : Per cent Lees than 0.1-0.2% CO? 0.1% Con cos
3
i~. n
10 20 27 SO
462 270 215 174
495 300 225 185
10 10 10
10 20 27
330 250 222
360 275 241
81
70
FIQURE 2. EFFECT OF CARBONDIOXIDECON60
.a)
P 50 -L
TENT ON MAXIMUM RATE OF SCRUBBINGWITH
TETRAMINESOLUTIONS WITH REDUCTION OF CARBON DIOXIDETO LESS TH.4N
40
30
20
2.5 2.5 3.0 3.0 3.0 3.0 3.0
40 50 50 60 300 300 175
0.0 1.9 0.0 1.5 12.0 14.9 10.6
37 37 37 37 36.5 37 37 37
80
2 20 21 22 23 1-2 3-4 5
39 40 40 40 41 39.5 39.5 40
Tetramine is the trade name of a mixture of polyethylene amines which will be marketed in the near future. The principal constituents are diethylene triamine and triethylene tetramine. Five per cent of the Tetramine mixture distills below 200" C. and 10 per cent above 300" C. These and similar compounds were described by Wilson ( d ) , and their use as absorbents for acidic constituents of a gas was patented b y Perkins (3). It was found that 50 per cent solutions were too viscous; the good results obtained with more dilute solutions, however, justified more extensive tests than were made with the ethanolamines. Table I1 gives results obtained at a liquid flow rate of 2.7 liters per hour using 5 , 10, and 2-5 per cent solutions of Tetramine and gas mixtures containing from 3 t o 80 per cent carbon dioxide, as well as a few results for 10 per cent solutions of Tetramine a t liquid flow rates of 3.6 liters per hour. With a single exception, the data in
j
Triethanolamine .. 40.0 40.0 .. 40.0 .. 40.0 40.0 43:O 47.5 48.0 47.0 48.5
Tower Temp., ' c Max. hfin.
Regenerated amine used. Tower not cooled.
Di- and triethanolamines were used in solutions containing 50 per cent by weight of the amine. The results obtained are reported in Table I. The amine solutions used in all T A B L E I. ABSORPTIOSO F CARBOX DIOXIDE FROM 80 P E R CEXT HYDROQEN-20 P E R CENT C A R B O N DIOXIDEMIXTCREBY 50 PER CENTSOLUTIONS OF DI- AXD TRIETHANOLAMINE
-
10
Inlet gas, liters per hour
0.1
PER
CENT
I I I A I . 4 \ 1 1 K\(;J
1315
Table TI were obtained with virgiii solutions of Tetramine. hy Mfiison and 1)odge (3). 'Tlmc results are iu fair a g r w In the single run made with a Tetramine soliltion regenerated merit for diethamrl;tmine, but. for the triethaiiolamine at by boiling, the permissible gas flow was approximately 8.5 ciirhon diuxidc partial pressures leas than 0.5 atniorphere the per cent as great as for the virgin soliition under the stime soluhilitic~sgiven by Rott~iwnsare riiucli greater than the prohaconditions. One run was made without cooling the column; bly more accuriite rcsiilts of Mason a,rid Ikidgr. For tlic diirririr experiments. crude calculations indicate tliat the temperntiire of the amine solution rose 10" C . in passing throiigh the tower, and tlic permissible gas Row iimemeci hhirrg tower was eyuivaleiit to three theoretical from 350 to 375 liters per Iioiir. This rim indicates t.iiat tlrc plates, :it most. Conrpa,risonwith distillation experiments in columns c,i similar construction givcs :iii estimated equivalent, tower tcmperatiiro is not a critical variable. Comliariscm of $he runs with 10 per cent Trtraririiie solutions at liquid of five: to eight theoretical plates. Tlie M w e n c c is not surflow rates OS 2.7 nird 3.6 liters per hour sliows t h t , tlic ~ m - prising in view oS the relatively high viscosity of the scrirbrnissible gas flow is proportional t o tlic liqiiiil HOW bing soliit,iiio.
Literature Cited
C O M l ' . ~ l l I S O of ~ Tables I am1 11, taking accwrrt of 0 rediiccil efficiency of regeenerateil Tetramino, sliows that a 5 per cent Tetramiire sdiition e m scrub approxinratcly 55 tlic,
per cent &i much gas as a 50 per cent dietlranolainine solutiivirion Gas Pim Cl8emistry at the QZod Meeting oi the Ameiiasn Clisreienl Roaiety, Pitta. burdi. Pa., Swterrrhei 7 t o 11, 19SB. Published by peimisxirm of tbe I>iiectn", 7'. s. nuroeir of .wine% (Not subject t o aogy,iy1,t., I t ~ a + ; ~ u AuCust m>
L'ALCHIMISTE SURPRIS PAR L'AUBE BY Leon Brunin Thanks t,u the eo6pera,t,ion01 the Frioh Art Reierence Library (New York), X I , . 71 in the Berolzheimer Series of Alchemicat and Ilistorical Reproductions brings tho work of an artist new to the series. Leon Brunin was born in Antwerp in 1861, studied at the Antwerp Academy, arid has become well known &s a painter and etchor. His work IIILS largciy been historical, genre, and interiors, and stan& out for its conscientious exoeution, with coloring like that of bhe old masters. The vrigiild painting is 2Za/a by 211/* inches, vas exhibited at the Salon den Champs Elydcs, Paris, 1896, and was sold in Antwerp in 1902 in the sale oi thr, collection of E. Euybrecht.
